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What is the hypophyseal-portal circulation?
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Endocrine system
The glands of the human endocrine system.
The hypophyseal-portal circulation (also known as the hypothalamic-hypophyseal portal circulation) is a specialized vascular system that provides a direct chemical pathway between the hypothalamus and the anterior pituitary gland.12
This system functions as follows:
- Origin: It begins in a capillary bed located in the median eminence of the hypothalamus, where neurosecretory cells discharge neurohormones—often called releasing hormones—into the blood.123
- Transport: These capillaries merge to form a plexus of veins surrounding the pituitary stalk, which then directs the blood into a second capillary bed within the anterior pituitary.12
- Function: By delivering hypothalamic hormones directly to the anterior pituitary, this circulation allows the central nervous system to precisely regulate the secretion of pituitary hormones while largely bypassing the general circulation.123
This arrangement is essential for the body's endocrine regulation, enabling the brain to control the activity of the pituitary gland and, by extension, other endocrine glands in response to internal and external environmental demands.23